In the mid-1990s, the boom in plastic bottles reached Europe and the business exploded with the corresponding moulds. The son of the company founder Otto Hofstetter, who had taken over the management in 1997, decided on a largescale expansion of production capacities: he intended to develop in-house production capacities for the preform plates, which had previously been manufactured externally. Of course, this meant that new machines had to be purchased, as the maximum workpiece size of the existing milling centres meant that they were far too small. Depending on the mould, the plates are up to 1.5 × 1 metres in size, 20 centimetres thick and 2,500 kilograms in weight, with a high level of precision required. A mould can have up to 144 cavities and the tolerance across the five base plates – which together form one mould – is less than one hundredth of a millimetre. After all, the base plates not only have to be exact in themselves, but they also have to be a perfect fit with each other.

So Hofstetter ordered the first of a total of three HEC 1250 machines, each with three pallet areas. The two additional machines followed. The third machine even enabled enough capacity to produce additional components in-house again, which were previously assigned to suppliers. The three machines stand next to each other in the purpose-built hall. Albert Kuster, Department Manager for mould base plates, is particularly impressed by the tool magazines of the HEC 1250: “Other machines feature chain magazines, which make the moulds difficult to access as you can only unload them from an unloading station. The Starrag Group systems use magazines with four towers each, where each mould is stored in four profiles, one on top of the other on the side. You simply look for the corresponding mould at an operator station, rotate the relevant tower, then open a door and remove the mould.”

The three systems have wear monitoring systems, which measure the required torque of the spindle during cutting and use this to calculate the status of the processing tool. In addition, breakage monitoring is carried out using laser measurement systems for workpiece measurement, so that long unmanned machining operations are also possible. If a mould ruptures, the machine auto- matically continues to function with a replacement mould – if possible – or notifies the on-call employee via mobile phone. This means the machining oper- ations, which can last up to 12 hours per workpiece, can be performed very efficiently overnight or at the weekend, without requiring shift work. This is an important factor in a country with high wages such as Switzerland. “We average around 21 hours of running time seven days a week,” Zatti adds. “The remaining three hours are spent on retrofitting and maintenance work. We are extremely happy with this high level of availability offered by the machines.”

“Our wishes are heard,” Zatti continues, “and that is a good feeling. The three machines – and the new hall for them – were a major investment for our company. Thanks to the speed with which the machines were commissioned, we were able to start recouping the capital spent on the machines straight away. That is crucial in terms of the return on investment. Our injection moulding tools are used to produce up to one million preforms a day; this is only possible with the most stringent requirements for the mould and its manufacture. It’s not without good reason that we are number two globally when it comes to PET moulds. We have achieved this position with maximum quality and short delivery times, and the HEC 1250s are a key factor in our success on both counts.”

When it comes to the collaboration with the manufacturer, Zatti’s response is purely positive: “The product is right, the price is right, the service is right – this has been confirmed time and again with seven machines from the Starrag Group over the course of many years. Our relationship with our suppliers is a partnership, not a typical supplier rela- tionship, and that has always worked perfectly with the Starrag Group – especially in times when we have disagreed on things. If you want to move mountains, you need a reliable partner – and we have found this in the Starrag Group!”